1. Field of the Invention
The present invention is generally related to an internal combustion engine lubrication system and, more particularly, to a lubrication system that pumps pooled oil from the collection location of one cylinder, through an inter-cylinder wall, and into an adjacent cylinder.
2. Description of the Prior Art
Internal combustion engines have been known for many years, including lubrication systems for preventing damage due to wear between sliding surfaces.
U.S. Pat. No. 2,556,273, which issued to Hedges on Jun. 12, 1951, describes an internal combustion engine cylinder lubrication system. It relates generally to internal combustion engines and, more particularly, to an improved means for supplying a constant and uniform flow of lubricating oil to the internal wall surfaces of the piston cylinders to lubricate the pistons during the reciprocation within their respective cylinders. The system is auxiliary to the oil rings conventionally fitted upon the piston.
U.S. Pat. No. 4,672,931, which issued to Biagini on Jun. 16, 1987, describes a lubrication system with oil recovery for a two-stroke engine piston with a sump pump for scavenging. The lubrication system with oil recovery for a two-stroke engine piston consists of a lubricating oil pressure circulation system having inlet and outlet holes for the oil. The holes pass through the wall of the cylinder. It further comprises shaped scraper rings, each ring being housed within a circular housing or seat obtained on the outside skirt of the piston. The circular housings are provided on the skirt of the piston at a height which does not allow any overlapping on the scraper rings on the transfer ports of the two-stroke engine.
U.S. Pat. No. 4,993,380, which issued to Hsu on Feb. 19, 1991, describes a lubrication mechanism for an engine cylinder. The mechanism includes upper and lower ring troughs on the inside wall of the engine cylinder. The two ring troughs can accommodate oil pipes and ring oil nets. The oil pipes includes an inlet pipe and an outlet pipe. Channels and numerous oil pores are defined by the pipes to allow the entrance of lubricating oil into the oil pipes, and seepage from the pores on the oil pipe, through a ring oil net to provide lubrication to the inside wall of the cylinder. The lubricating oil then flows downwardly to the lower ring oil net, through the net and the oil pipe, and into an outlet pipe for discharge.
U.S. Pat. No. 5,611,302, which issued to Duvinage et al on Mar. 18, 1997, describes a two cycle internal combustion engine with unidirectional flow scavenging. In a two cycle internal combustion engine with unidirectional flow scavenging, a piston is disposed in a cylinder so as to movable between top and bottom dead center end positions, the cylinder has fresh air inlet passages which are so arranges to that their bottom walls are disposed below the piston top edge when the piston is at its bottom dead center position so that part of the piston top land is directly exposed to the fresh air through the air inlet passages and oil discharge bores extend from the air inlet passages and are in communication with the oil circulating system for the removal of oil wiped off the cylinder wall and collected in the inlet passages.
As is known to those skilled in the art, internal combustion engines used in outboard motor applications are typically arranged so that the crankshaft's axis of rotation is generally vertical. This places the cylinders in one or more vertical rows, depending on the number of cylinders in the engine. The vertical arrangement of the cylinders can create several problems.
One problem faced by internal combustion engines, particularly those used in marine applications, is that the cylinder walls are sometimes difficult to lubricate properly. It is important to provide lubrication on the cylinder walls to prevent excessive wear because of the sliding contact between the piston rings and the cylinder wall. Another problem faced by internal combustion engines used in marine applications is the pooling of lubricant at certain collection locations. In order to properly lubricate the sliding surfaces of an internal combustion engine, it is beneficial to cause the lubricant, such as oil, to flow along the surfaces toward locations where two surfaces slide on one another or, alternatively, to spray a lubricant mist on these potential wear surfaces. When lubricant pools within the crankcases or cylinders of an engine, the pooled, or puddled, lubricant does not fulfill a useful function. In addition, pooled lubricant is often drawn into the combustion chamber and burned. This can create excessive smoke in the exhaust.
It would therefore be significantly beneficial if a lubrication system could be developed that both improved the lubrication of the cylinder walls and avoided excessive pooling of lubricant in puddles.